The present systems and methods relates-to contact lens packaging and more particularly, to an improved economic form of package for a contact lens which satisfies lens packaging criteria, including sterility and environmentally sensitive disposability.
Prior Art
Soft disposable contact lenses are commonly contained in disposable packages. As packaging adds to the overall cost of the lens, it should be made as economically as possible but without compromise to the requisite packaging criteria. The traditional blister pack packaging (shown in FIGS. 1-3) for disposable lenses (both bi-weekly and daily) consists of a polypropylene receptacle for the lens (herein after referred to as a “boat”), topped by a multi-layer film consisting of polyethylene, aluminum, a bonding agent and polypropylene. The boat is usually an injection molded plastic which has high stiffness but is capable of limited elastic deflection and includes a preformed recess. The boat is filled with a suitable storage solution, preferably saline, and receives a single lens in situ. The blister pack is then autoclaved using steam and pressure to terminal sterility. These blister packs are presented to the patient in boxes of individual packs (FIGS. 4-5) or as multiple blister strips.
The marketing objective is to present the contact lens to a patient in an aesthetically pleasing package that both satisfies the statutory requirements for sterility and stability, and allows the patient to remove the lens safely and easily. The packaging is used only once and is discarded after the lens is removed. This impacts the costs of the lens/package combination. In order to reduce the overall price of the lens to the patient, the cost of the packaging should be kept to an absolute minimum. In addition, disposability of lens packages necessitates conformity with ecological standards.
The lens must be kept hydrated while in the package. The package must be well sealed and should minimize water vapor transmission through the boat and laminated layer to maximize the shelf life and prevent drying out of the lens contained therein. In use, the user removes the laminated material from a flange formed on the boat by peeling back the cover to expose the lens immersed in a hydrating solution.
A variety of contact lens packages, particularly disposable contact lens packages including preformed blister packs, are taught in the prior art. As exemplified in the prior art, conventional wisdom in the contact lens industry has been to provide preformed stiff packaging which protects the lens from damage from applied load. Examples of typical prior art blister packs are shown in: U.S. Pat. Nos. 5,704,468; 4,392,569; 5,620,087; 5,620,088; 4,691,820; 5,823,327; and 5,853,085; EP Publication No. 1092645 A1; and EP Publication No. 0 129 388.
Flexible retort packages are also known, however, not for use with contact lenses. U.S. Pat. No. 4,769,261 discloses a seal layer for use in large institutional sized retort pouches comprising an ABA film structure, wherein the A layers are each composed of a blend of a minor amount of an elastomer and a major amount of a polyolefin and the B layer is composed of a blend of a major amount of an elastomer and a minor amount of polyolefin. Retort pouches made with the ABA film structure as the seal layer exhibit improved impact strength. There is no teaching in the '261 patent to use a retort package for housing a contact lens.
There is a long felt need in the disposable contact lens industry to provide an economic, space-efficient, and convenient, disposable contact lens package without compromise to durability, sterility and utility of the lens.